The long, slow build for the Lil' Lady

[2manyoranges]

Re: The long, slow build for the Lil' Lady - ?Weightweenie?

No engineering drawing and overloaded at work at the moment but I can send some sketches through...

 

[RickTheUncivil]

Re: The long, slow build for the Lil' Lady - ?Weightweenie?

No engineering drawing and overloaded at work at the moment but I can send some sketches through...

No worries, I can see what I can find online. If I'm going to make something it's the measurements that would be particularly helpful if you had something already, but if not no worries.

 

[RickTheUncivil]

Re: The long, slow build for the Lil' Lady - ?Weightweenie?

Weightweenie again - gears this time: Chainsets

Lets assume the aforementioned in-hub gears idea goes nowhere and I stick with a cassette at the rear, maybe with single ring but probably with the option for double or triple rings. I’ve been on the lookout for a crankset with slightly shorter arms to give shorter legs a bit of a chance to go all the way around and to help with ground clearance on the smaller wheels.

Thanks to help on the forum I was pointed towards Spa Cycles and these seem to be a decent option - a simple crankset available down to 160mm at £25 or include rings at £35, that’s a good price I’d say. Other shorter ones are available but more costly like these from KidsRacing.

The Spa full set comes in at 510g (for the 170mm) cranks or 705g including triple rings, and one on the kidsracing site comes in at 440g (yes, they are shorter so direct comparison is probably not fair). But is that good? Never thought about it before. Comparing to some of the spares in the shed and with some figures from weightweenies:

Ultegra 6500 (octalink, 172.5, double, inc rings) 682g
XTR M952 (octalink, 175mm, triple, inc rings) 685g
XT 739 (square taper, 172.5mm, triple, inc rings) 688g
XT 750 (square taper, 175mm, triple, inc rings) 748g
Alivio (square taper, 175mm, triple, inc rings) 878g

So 705g is actually looking pretty good against the competition. Lighter than my benchmark XT M750 and not far off Ultegra/XTR, and ~20% lighter than a basic Shimano jobbie. Not bad at all. And consider that a new XT crankset is over £100 too. Add on a BB, a UN52 is around the 300g mark, UN72 more like 250g. Let’s call it a nice round 1kg for the set of cranks, chainrings and BB.

Now then, if we move away from square taper and look alternative formats theres not much to be saved really in the BB between octalink spline drive vs square taper. Hollowtech arms maybe a smidge to be saved, maybe not. But HT2 looks to bring an XT set in at just over 800g and xtr / dura-ace level kit in at just under 800g, so HT2 might be a way to go to drop another 100-200g from the build.

Keeping the eyes open for a nice, light, HT2 style double or triple with sensible sized rings / BCD and short arms. Else I’m off shopping with Spa Cycles I guess.

 

[RickTheUncivil]

Re: The long, slow build for the Lil' Lady - ?Weightweenie?

Impulsive and possibly ill-thought-out buying has happened details to follow once they arrive but for now let’s say we are using 32H rims which won’t support a rim brake, so its disc or roller/drum brakes. Let’s assume disc brakes as default unless, I find the aforementioned bargain hub gear and brake setup.

So, hubs, whats in the shed? I need a standard 100 and 135mm OLD, standard QR fitting ready to take a disc brake (and I still have my eye on the weight). Not much to go at really, some good non-disc hubs, plenty of 36H hubs etc….

Front: NIB Shimano Deore M555 (funny flangeless jobbie), black, disc ready (6 bolt), 297g
Rear: NIB Shimano XT M756. Black, disc ready, 486g

That's it. I guess an XT rear and Deore front options as a starting point then. What alternatives though?

Lots of cheap sets on ebay, Chinas finest no doubt, are throwing up some options. For example, a £24 F&R set stated as 238g front and 425g rear. That’s a weight saving of around 60g per wheel over the Shimano benchmark. A F&R set the same weight but with sealed bearings rather than loose balls is roughly double the price. I expect these are not the highest quality but given the intended use they may be just the ticket.
I took a quick look on ebay and the other usual online retailers looking for known brands comparison:

Novatec front, stated as 219g at £11
SRAM 506 front, stated as 230g at £14 (used)
Shimano Deore M6000 front, centrelock, 245g at £13
Shimano Deore M615 rear, centrelock, 440g at £15

…which tells me that a decent enough hub up to 25% lighter than the ones in the shed can be got for not much money, which is nice. I would like matching hubs or at least similar (the Deore front and XT rear are similar enough for me, at least they are the same colour).

Anyone got some alternatives for me?

 

[elPedro666]

Re:

https://www.sjscycles.co.uk/hubs-intern ... l-36-hole/

I'm a big fan of these, but as far as I can see they only come in 36h, annoyingly. Plus at ~1.2kg (rear) I guess that's getting close to 400g more than an equivalent disc setup...

They feel lovely to use though, and so simple to maintain

 

[RickTheUncivil]

Re:

Yeah seen them, as you say they do a good job but the weight penalty is a bit of a killer. For brake and gears in the hub it's less of a penalty but a lot more cost.

Still thinking

 

[Fatal Swan]

Re: The long, slow build for the Lil' Lady - ?Weightweenie?

The chainset discussion is going back a bit now (sorry), but I always felt the XT Octalink chainset (M752) was the bang-for-buck sweet spot for the cost-conscious weight weenie. Chainset is around 625g and the XT level BB is just over 250g. Compared with a Hollowtech II setup that's basically the same weight as an M760 setup and a fraction heavier than an M770.

That said, I've more or less given up on the Octalinks now as it's just more useful to use the same Hollowtech BBs if you swap out the cranks very often and the good Octalink XT bottom brackets are getting harder to come by.

 

[RickTheUncivil]

Re: The long, slow build for the Lil' Lady - ?Weightweenie?

i hear you on the octalink issue, not exactly a persevering format. The same issue puts me off buying and using ISIS splined drive kit too.

i weighed my M750 chainset at around 750g, square taper rather than octalink but still where the hell have I gained over 100g there?

The bigger issue for this project though is getting short enough cranks, 170-175mm is fine for XT but getting one in kiddy size just isn't going to happen.

 

[Fatal Swan]

Re: The long, slow build for the Lil' Lady - ?Weightweenie?

i hear you on the octalink issue, not exactly a persevering format. The same issue puts me off buying and using ISIS splined drive kit too.

i weighed my M750 chainset at around 750g, square taper rather than octalink but still where the hell have I gained over 100g there?

I've never had an M750 myself to weigh, but the M752 has Hollowtech arms which I guess might explain the difference? Weightweenies has the same kind of weights for the M752 as I do: https://weightweenies.starbike.com/list ... =cranksets

Unless your M750 has larger chainrings with a 48t large ring, which would also explain it?

 

[RickTheUncivil]

Re:

I thought that 750 were Hollowtech but you could well be right.